1. Field of the invention
The present invention relates to a saccharide in the form of powder (abbreviated as "saccharide powder" hereinafter), and its preparation and uses; more particularly, it relates to a saccharide powder, i.e. a panose-rich saccharide containing oligosaccharides together with 48-93% panose (the symbol "%" means "w/w %" throughout the specification as long as no inconvenience occurs), based on the weight of the dry solid (abbreviated as "d.s.b." hereinafter), as well as exhibiting a crystallinity of 19% or higher on x-ray powder diffraction analysis, and its preparation and uses.
2. Description of the Prior Art
As evident from Japanese Patent Publication No. 76,063/83, The Nippon Dental Review, No.498, pp.161-171 (Apr., 1984) and The Japanese Journal of Pediatric Dentistry, Vol.25, No.3, pp.608-613 (1987), it has been known that (i) dental-caries-inducing microorganisms do not assimilate panose to form water-insoluble glucans, (ii) the formation of water-insoluble glucans from sucrose is strongly reduced when the microorganisms assimilate sucrose in the presence of panose, and (iii) the microorganisms do not assimilate panose to form organic acids, and these render panose advantageously useful as a sweetener having a relatively low- or anti-dental-caries-inducibility, as well as a growth-promoting saccharide for bifid bacteria.
It has been known that a saccharide solution containing panose together with a relatively-large amount of monosaccharides such as glucose and fructose; oligosaccharides such as maltose, isomaltose, maltotriose, isomaltotriose and isomaltosyl maltose; and dextrins is obtained by conventional methods, for example, (1) a process containing a step of subjecting maltose to the action of .alpha.-glucosidase (EC 3.2.1.20), (2) a process containing a step of subjecting a mixture of maltose and sucrose to the action of sucrase (EC 2.4.1.5) and (3) a process containing a step of subjecting pullulan or an amylaceous substance to the action of an acid or an enzyme such as .alpha.- and .beta.-amylases.
It has been also known that a preparation of a saccharide powder comprising subjecting a saccharide solution prepared by the above conventional preparations to a column chromatography using a strongly-acidic action exchange resin to mainly remove monosaccharides, recoverying a panose-rich fraction with an increased panose-content, concentrating the fraction, and pulverizing the resultant.
The panose-rich saccharide powder thus obtained is, however, usually a mixture of saccharides containing a relatively-large amount of panose and other oligosaccharides.
When the panose-rich saccharide powder is used in food products, the coexistence of oligosaccharides does not hinder the properties of panose as long as the amount of the oligosaccharides dose not reach an excessive level, and improves the yield of the final saccharide product. These may result in an economical benefit and a promotion of an industrial preparation of panose.
It was found that a saccharide powder containing a relatively-large amount of panose together with other oligo-saccharides, however, has the following drawback: Since the saccharide has a relatively-high hygroscopicity, it readily solidifies to lose its free-flowing ability. Thus, a relatively-high level of care for the packaging and handling is inevitable.
In the preparation of a panose-rich for providing saccharide powder, there has been a great demand a saccharide powder having a substantial non-hygroscopicity and a satisfactory stability and free-flowing ability by improving the properties of a relatively-high hygroscopic saccharide-powder which contains 7% or higher of oligosaccharides, d.s.b., and has an economical advantage of a relatively-high yield.